Triple valve.



- PATENTED MAR. 21,1905.

C. E. BARRY.

TRIPLE VALVE.

APPLIGATION FILED sBPT.e,19os.

Inventor. Charles Earry.

UNTTED STATES Patented March 21, 1905.

PATENT OEEICE.

CHARLES BARRY, OF SCHENECTADY, NENV YORK, ASSIGNOR TO GEN- ERAL ELECTRICCOMPANY, A CORPORATION OF NEV YORK.

TRIPLE VALVE.

SPECIFICATION forming part of Letters Patent No. 785,537, dated March21, 1905.

Application tied september s,19os. serai No. 172,272.

T0 all wtmn it muy concern:

Be it known that I, CHARLES E. BARRY, a citizen ot' the United States,residing at Schenectady, county of Schenectady,State of New York,haveinvented certain new and useful Improvements in Triple Valves, oil whichthe following is a specilication.

My invention relates to automatic airbrake systems-that is, systems inwhich the brakes are applied by a reduction in the pressure of air inthe train-pipe-in contradistinction to "straight air systems, in whichthe brakes are applied by an increase in such pressure. In systems ofthis type each car is provided with a brake-cylinder, an auxiliaryreservoir which is supplied with compressed air from a train-pipe, and aso-called triple valve, which operates upon a reduction ot' pressure inthe train-pipe to admit air from the auxiliary reservoir to thebrake-cylinder to apply the brakes and upon an increase of train-pipepressure to cut olf the supply connection with the auxiliary reservoirand to exhaust the brake -cylinder to release the brakes. My inventionhas particular reference to the triple valve; and one of its objects isto provide a novel form of valve `loy which the engineer may control therelease ot' the brakes, so as to maintain any desired braking pressurein the brakecylinderin other Words, to provide an improved means forgradually releasing the brakes and stopping' the releasing operation atany desired point. In the case of systems now in common use seriousdiliiculties often arise in the handling of long trains because ot' theinability of the engineer to partially release the brakes. In suchsystems the brakes on each car are fully released at a single operation,and the releasing action also takes place on the dilferent cars insuccession, so that often when the brakes are released While the trainis running at a considerable speed the head or' the train, having thecheck to its speed suddenly removed in advance of the rear, movesforward with such force as to break the train into two or more parts. Bythe employment of my invention this difliculty is overcome.

Another object of my invention is to provide a valve mechanism whichshall be economical in operation and by which large variations inbrake-cylinder pressure may be produced by small variations intrain-pipe pressure, so that a maximum brake application may be obtainedwith a relatively small reduction of pressure in the train-pipe, and,conversely, a great restoration of pressure in the brakecylinder with asmall restoration of trainpipe pressure.

Other objects and advantages of my invention will appear from thefollowing detailed description, taken in connection with theaccompanying drawings, in which- Figure 1 is a view illustrating, partlyin diagram, one embodiment of my invention and showing the triple valvewith its piston in application position; and Figs. Qand 3 are similarviews of said valve with the piston in lap and release positions,respectively.

Referring in detail to the drawings, 1, 2, and 3 designate the usualbrake-cylinder, auxiliary reservoir, and train-pipe, respectively, withwhich the triple valve is associated. The train-pipe and the auxiliaryreservoir are connected by a pipe 4, which permits a flow of air fromthe train-pipe to the auxiliary reservoir and through the agency of acheckvalve 5 prevents a flow in the opposite direction. A supplementalreservoir 6 is connected with the reservoir 2 by a pipe 7, which 8O isprovided with a check-valve 8, arranged to permit a flow of air onlytoward the supplemental reservoir. The triple valve comprises a casing9, provided with suitable ports and connections, and a piston 10 forcontrolling 85 said ports. A transverse partition 11 within the casingdivides its interior into two compartments, in which are located theheads 12, 13, 1,.and 15 of the piston 10, the heads 12 and 18 occupyingthe upper compartment and 90 the heads 14 and 15 the lower. A pipe 16,leading from the supplemental reservoir. 6 to the upper end of thecasing 9, supplies air to the upper face of the head 13, and this air byreason of the small displacement otl the head 13 relative to the volumeof the supplementalreservoir exerts a practically copstant pressurewhich tends to move the piston toward the lower end of the casing 9. Apipe 17, leading from the train-pipe 3 to the upper compartment,supplies train-pipe air to the lower side of the head 12, and a port 18maintains the air in the space between the heads 12 and 13 atatmospheric pressure. Brake-cylinder air is supplied to the lower sideof the head 15 and both sides of the head 14 through the pipes 19 and20. The pressures on the lower side of head 15 and the upper side of thehead 14 balance each other, so that they have substantially no influenceupon the movement of the piston, the only pressure tending to move thepiston being on the lower side of the head 14, reacting against thelower head of Ithe valve-casing'. This pressure, in conjunction with thetrain-pipe pressure acting on the lower face of the head 12, opposes thesupplemental reservoir pressure acting upon the upper face of the head13. vAn exhaust-port 21 communicates with the lower compartment and whenthe parts have moved to the position shown in Fig. 3 provides anescape-opening for the brake-cylinder air. Another port, 22,communicateswith the lower compartment at a point adjacent to the partition 11, soas to maintain the air on the upper side of the head 15 always atatmospheric pressure. A pipe 23 connects the auxiliary 'reservoir 2 withthe lower compartment of the casing 9 at a point somewhat below thebrake-cylinder port, the distances between the heads 14 and 15 andbetween the auxiliaryreservoir, brake-cylinder, and exhaust ports beingso proportioned that communication may be established between thebrake-cylinder and the auxiliary reservoir or between the brake-cylinderand atmosphere, or both auxiliary-reservoiisand exhaust ports maybeclosed, as illustrated in Fig. 2.

In operation the piston 10 is balanced between supplemental-reservoirpressure on the one hand and combined brake-cylinder and train-pipepressures on the other, and when the train-pipe pressure falls off thebrake-cylinder is charged from the auxiliary reservoir to restore thebalance, and when the train-pipe pressure increases the brake-cylinderis exhausted sufficiently to make up the difference and again restorethe balance.

Considering the operation more in detail, as soon as the enginee1"svalve is moved to admitair from the main reservoir to the trainpipecompressed air will iiow from the trainpipe through the pipe 4 to theauxiliary reservoir and thence by way of the pipe 7 supplementalreservoir 6, and pipe 16 to the upper side of the piston-head 13 in thecasing 9 and from the train-pipe through the pipe 17 to the lower sideof the head 12. If the auxiliary-reservoir port is uncovered by the head14, air will also flow into the brake-cylinder from the auxiliaryreservoir; but if said port be closed the brake-cylinder will remainuncharged, and atmospheric pressure only will act on the lower face ofthe head 14. vIn either event the piston 10 will be moved to theposition illustrated in Fig. 3, since the force on the lower side of thehead 12 will overcome the opposing force on the upper side of the head13 whether the pressure in the brake-cylinder be at that of atmosphereor greater, since the area of the head 12 is greater than that of thehead 13 and the intensities of the pressures in the supplementalreservoir and train-pipe are equal. Vhen this, the release or running,position of the piston is attained, any air that may have been fed tothe brake-cylinder before such movement will be exhausted therefrom byway of the pipe 19 and the port 21. W' ith the parts thus charged, if itis desired to apply the brakes for an ordinary service stop thetrainpipe pressure is reduced until the pressure acting on the lowerside of the head 12 bccomes less than that acting on the upper side ofthe head 13. This difference will cause the piston to move toward theleft until the head 14 partially uncovers the auxiliary-reservoir port.Air will then liiow from the auxiliary reservoir to the brake-cylinderand continue to flow until the pressure on the lower side of the head 14has increased suiliciently to neutralize the effect of reduction ofpressure on the lower face of the head 12 and move the piston upwardsuliiciently'to cut off the auxiliaryreservoir supply. This will bringthc piston to the lap position. (Illustrated in Fig. 2.) fhen air liowsfrom the auxiliary reservoir into the brake-cylinder, it will force thebrake-cylinder piston toward the left to apply the brakes. If anincreased brake application is desired, a further reduction in train-pipe pressure is made. This will again cause the piston to move toward theleft, so as to partially uncover the auxiliary-reservoir port, andthereby admit air to the brakecylinder untilthe brake-cylinder pressurehas risen sufficently to counteract the effect of the train-pipe-pressure reduction, and thereby again force the parts to lapposition, as before. Vhen it is desired to release the brakes, theoperation is substantially the same as that which takes place whencharging the system, as previously described-that is, the trainpipepressure is increased and the piston is moved toward the right, so as towholly or partially uncover the exhaust-port 21 and cover theauxiliary-reservoir port, and thereby allow air to escape from thebrake-cylinder to atmosphere. The amount of air that may escape from thebrake cylinder, and therefore the degree ofr brake-cylinder red uction,will depend directly upon the increase of train-pipe pressure. Forinstance, if the train pipe pressure 'increase is small, the necessarychange in brake-cylinder pressure will also be small.` On the otherhand, if a considerable increase of train-pipe pressure is made it canonly be neutralized by a considerable reduction in brake-cylinderpressure. It will also be apparent that in applying or releasing thebrakes more or less of the auxiliary-reservoir port or the exhaust-port21 will be uncovered, according to the amount of train-pipe variation.Such intermediate positions of the piston are shown by the dotted linesin Figs. 1 and 3. Where the reduction in train-pipe pressure is large,the parts will be thrown to the position shown in Fig. 1 and thebrake-cylinder will be charged rapidly, and where the train-pipepressure is increased suddenly the parts will be thrown to the positionshown in Fig. 3, and the brake-cylinder will exhaust rapidly.

As to the proportioning of the various parts of the valve, it should benoted that the heads 14 and 15 are, in effect, a single head with a deepannular port whose depth may be varied as desired and that the size ofthe head 13 determines the effective pressure oi' the entrappedsupplemental-reservoir air in that end ol the casing, and Variations ot'the size oi' said head will only correspondingly vary said pressure. Onthe other hand, variations of the areas of the heads 12 and 14 will.produce different brake-cylinder-pressure variations corresponding toany given train-pipepressurevariations. In the preferred form oi' theinvention the head 12 is made somewhat larger than the head 14, so thatslight variations of pressure in the train-pipe will produceconsiderable variations of pressure in the brake-cylinder. This will beapparent upon consideration of a specilic case. For this purpose let itbe assumed that the area of the head 12 is two square inches, that ofthe head 14 one square inch, and that the maximum train pipe pressure isseventy pounds per square inch. Under such conditions it will beapparent that with seventy pounds pressure in the auxiliary andsupplemental reservoirs and in the train-pipe the parts would assume theposition illustrated in Fig. 3 and that a five-pound reduction in trainpipe pressure would reduce by ten pounds the effective pressure exertedupon the lower side of the head 12, and in order to neutralize this lossof pressure and bring the piston to the lap position (illustrated inFig. 2) a brake-cylinder-pressure variation slightly greater than tenpounds acting upon the one-square-inch area of the head 14 would berequired. Similarly a train-pipe reduction oi' ten pounds would befollowed by a brakecylinder increase slightly greater than twentypounds, and so on, each train-pipe reduction causing' a correspondingincrease of substantially twice the value. This action would continueuntil the train-pipe pressure had fallen to substantially thirty-tivepounds, when the brake-cylinder pressure would be a maximum, or'slightlyless than seventy pounds. Similarly in releasing the brakestrain-pipe-pressure variations between the limits thirty-ive and seventypounds would produce corresponding brake-cylinder-pressure variationssubstantially between the limits naught and seventy.` It will of coursebe apparent that since the brake-cylinder can only be charged by theexpansion of the air in the auxiliary reservoir it can never be chargedto the full seventy pounds pressure; but the maximum pressure will beslightly less than seventy pounds, and this will be balanced by atrainpipe pressure slightly less than thirty-five pounds, so that thelimits thirty-tive and seventy are approximate only.

I do not wish to be limited to the particular construction hereindisclosed, since it is apparent that many alterations and modiiicationsmay be made without departing from the spirit of my invention, and I aimto cover by the terms oi' the appended claims all such alterations andmodiiications.

What I claim as new, and desire to secure by Letters Patent. or' theUnited States, is

1. In an air-brake system, the combination of a train-pipe, abrake-cylinder, an auxiliary reservoir, a valve adapted to connectbrakecylinder to auxiliary reservoir or to atmosphere, a pistoncontrolling said valve and comprising two heads of unequal areassubjected to train-pipe pressure and to brake-cylinder pressurerespectively, and means for impressing on said piston a constant forceopposing said pressures.

2. In an air-brake system, the combination of a train-pipe, abrake-cylinder, a piston comprising two heads of unequal areas subjectedto train-pipe pressure and to brake-cylinder pressure respectively,means for impressingon said piston a constant force opposing saidpressures, and means operatively connected to said piston for varyingthe pressure of the air in the brake-cylinder.

3. In an air-brake system, the combination of a train-pipe, an auxiliaryreservoir, a brakecylinder and mechanism connected therewith, comprisinga movable member having abutments of unequal areas subjected, the largerto train-pipe pressure and the smaller to brakecylinder pressure, andmeans cooperating therewith for varying the pressure of the air in thebrake-cylinder.

4. In an air-brake system, the combination of a train-pipe, an auxiliaryreservoir, a brakecylinder and valve mechanism comprising a casingconnected therewith and provided with an exhaust-port and a pistonhaving a plurality of heads, means for entrapping compressed air in aportion of said casing adjacent to one of said heads, other heads beingsubjected to brake-cylinder and train-pipe pressures, and meanscooperating therewith for controlling the flow of air from the auxiliaryreservoir to the brake-cylinder and from the brake-cylinder toatmosphere.

5. In an air-brake system, the combination of a train-pipe, an auxiliaryreservoir, a brakecylinder, and valve mechanism for controlling the.iiow of air to and from the brake-cylinder, comprising means normallycutting olf the brake-cylinder supply and exhaust-passages under theequal opposing effects of a constant pressure on one side and combinedtrain-pipe and brake-cylinder pressures on the other and operating uponan increase or decrease of train-pipe pressure to establish acommunication to produce a decrease or an increase respectively ofthebrake-cylinder pressure to restore the equality.

6. 1n an air-brake system, the combination of a train-pipe, an auxiliaryreservoir, a brakecylinder, and a triple valve for controlling the Howof air to and from the brake-cylinder, comprising a movable membersubjected to a practically constant pressure tending to move it in onedirection and brake-cylinder and train-pipe pressures tending to move itin the opposite direction, the member being so constructed and arrangedthat a variation of one kind in the train-pipe pressure will establish aconnection to bring about a Variation of the opposite kind in thebrake-cylinder.

7 In an air-brake system, the combination of a train-pipe, an auxiliaryreservoir, a brakecylinder, a valve-casing, a piston therein having anupper and a lower head, means for entrapping compressed air in saidcasing at'the upper side of the upper head, a port for supplyingtrain-pipe air to said casing at the lower side of the upper head, aport for supplying brake-cylinder air to said casing at the lower sideof the lower head, an exhaust-port in said casing adjacent to thebrake-cylinder port and adapted to be closed by the lowerhead when thecombined train-pipe and brakecylinder pressures equal the pressure ofthe entrapped air and to be opened to establish communication with thebrake-cylinder port when the train-pipe pressure is increased, a portfor supplying auxiliary-reservoir air to said casing at a point belowsaid brake-cylinder port, and means for closing said auxiliaryreservoirport when the combined train-pipe and brake-cylinder pressures equal thepressure of the entrapped airr and for opening it to establishcommunication with the brakecylinder port when the train-pipe pressureis reduced.

8. In an air-brake system, the combination of atrain-pipe, an auxiliaryreservoir, a brakecylinder, a cylindrical valve-casing comprising anupper and a lower compartment, a piston therein having a head in eachcompartment, means ior entrapping compressed air at the upper side ofthe upper head, a port for supplying train-pipe air to the uppercompartment at the lower side of the upper head, a port for supplyingbrake-cylinder air to the lower compartment at the lower side of thelower head, an exhaust-port leading from the lower compartment adjacentto the brake-cylinder port and adapted to be closed by the lower headwhen the combined train-pipe and brake-cylinder pressures equal thepressure of the entrapped air and to be opened to establishcommunication with the brake-cylin-

